Let's hope that after this event, they'll add an offline mode (similar of what you can choose on Steam and Xbox Series consoles) in a future update of Piapro NT, because server issues can happen anytime.
Also, it's a good reminder that hacking problems can happen on any website, and where there are lots of customers data, it's more possible. So, it's always good to register to these websites (even Amazon, for example) with a secondary email account and a password different for each website. And when possible, use a charge debit card not linked to your bank account.
edit: even better of offline mode, an option to export your license key as a backup license file, and that can be used offline only on 1 pc at a time. If you change computer, you'll need to import that license file (to avoid piracy, that license could be used maximum 5-10 times, then need to use online again to make a new valid license key). It could be a good thing.